Objective is to develop pressure transducer preparations for chronic implantation in rats & mice. Specific aims: develop a 1.3 - 15 mm dia implantable transducer for rats; implantable mating cannula/flushing system for mice; skin button for rats; & electronics for systems interface. Rats & mice are replacing larger mammals in cardiac research for budgetary & societal reasons. No suitable chronic implantable pressure transducers are now available. Such preparations substantially reduce mortality & morbidity in host animals, permitting longer surveillance, better quality data Methodology for achieving goals: design/procure .23 x .30 mm strain gages (done); develop new metal/semiconductor interface to reduce baseline drift (done); design/fabricate prototype transducers (done); Utilize EDM to fabricate fine finish, stress relieved, hi-output diaphragm; develop & test surgical techniques and skin button/cannula systems for biocompatibility & instrument survivability. The Phase I prototype transducer met design goals, justifies feasibility of the following Phase II goals: long-term implantable survival; economic production design; implantable skin button (electrical plus infusion port); cannula systems for mice; support electronics. Experience with larger implantable transducers resulted in technology innovative extension to configurations in other species, organs, & applications. PROPOSED COMMERCIAL APPLICATION: Initially, viable commercial products for cardiovascular research in small mammals. Subsequently, other animal research (G.I., intracranial, bladder, intrauterine). Then, G.I. (ERCP especially) and urological in human clinical instrumentation